1. Field of the Invention
The present invention relates generally to an adapter device for a compact fluorescent lamp having an eyesight protection function, and, more particularly, to an adapter device for a compact fluorescent lamp that enables the additional emission of light having wavelengths that are not emitted by existing compact fluorescent lamps but are essential for color vision.
2. Description of the Related Art
Incandescent lamps (tungsten lamps, halogen lamps, and krypton lamps) have an advantage in that they are suitable for the protection of eyesight because they have excellent color rendering, and thus they emit light closest to natural light, unlike fluorescent lamps (general fluorescent lamps and compact fluorescent lamps). Accordingly, although they have a shortcoming in that they have high power consumption, they are widely used as home and business lighting apparatuses (for example, desk lamps) in many western countries and they are also used for high-quality illumination in Korea.
In contrast, since fluorescent lamps have worse color rendering than incandescent lamps but have very low power consumption, they are widely used as streetlamps and for hall lighting in many western countries, and they are widely used in homes and offices in Korea.
Meanwhile, as the costs of energy resources, such as petroleum, are increasing rapidly, many western countries, including the U.S., have recently established regulations stipulating that existing high-power consumption incandescent lamps be replaced with low-power consumption lamps by 2011 or 2012.
As a result, the development of low-power consumption lighting apparatuses having excellent color rendering is a pressing global issue. A conventional full-spectrum type fluorescent lamp (the lamp's CRI is around 90-95) and a Light Emitting Diode (LED) lamp have been proposed as solutions for this issue.
The full-spectrum type fluorescent lamp will be described first.
Of existing compact fluorescent lamps shown in FIG. 2, a conventional deluxe type fluorescent lamp (the lamp's CRI is around 80-85) is inexpensive (one to three dollar). However, since the fluorescent material applied to the inner glass of the deluxe type fluorescent lamp is mainly a phosphate, silicate or tungstate compound, large amounts of blue light in a wavelength range of 430 to 450 nm, red-orange light in a wavelength range of 600 to 620 nm and yellow-green light in a range of 530 to 560 nm are emitted, while small amounts of pure red light in a wavelength range of 620 to 700 nm and pure green light in a wavelength range of 498 to 530 nm, which are present in natural light in large amounts, are emitted, as shown in the upper graph of FIG. 1. Therefore, the deluxe type fluorescent lamp has problems related to color rendering and sharpness, and thus it causes eye fatigue when it is used for a long time.
In order to mitigate the shortcoming of the deluxe type fluorescent lamp, the full-spectrum type fluorescent lamp, which is constructed by adding a phosphorus compound to fluorescent material for the deluxe type fluorescent lamp and emits a large amount of light at red wavelengths, has been invented. However, it is impossible to manufacture it at low cost because the phosphorus compound is a rare material and very expensive, and the yield of the full-spectrum type fluorescent lamps capable of emitting five-wavelength light is very low, so that a true full-spectrum type fluorescent lamp costs more than several tens of dollars each. Furthermore, currently commercialized inexpensive full-spectrum type fluorescent lamps (about 5 dollars each) do not emit sufficient amounts of light at the additional wavelengths, even though there are referred to as full-spectrum type fluorescent lamps. Accordingly, the currently commercialized inexpensive full-spectrum type fluorescent lamps are far from being lamps for emitting natural light.
Next, an LED lamp will be described.
Currently, commercial Light Emitting Diodes (LEDs), which emit light having various colors, are being marketed. However, since manufacturing a lighting apparatus by combining LEDs for various colors so as to emit light similar to natural light requires hundreds of LEDs to emit sufficient light for such a lighting apparatus, a manufacturing cost higher than that for a deluxe type fluorescent lamp is incurred, and it is difficult to control the considerable amount of heat emitted from the hundreds of LEDs, with the result that it is not desirable to manufacture a lighting apparatus for emitting light similar to natural light using only LEDs, from the viewpoints of the manufacturing cost and the emission of heat.
Meanwhile, in western countries, tens of various lighting apparatuses for incandescent lamps, such as desk lamps and dining table lamps, are installed in each home. When the various lighting apparatuses for incandescent lamps are replaced with new lighting apparatuses pursuant to the established regulations, problems will arise in that a lot of expense will be incurred for the replacement of the lighting apparatuses and a lot of further expense will be incurred for the disposal of the lighting apparatuses.